Process of making refried beans containing an oil substitute and product thereof

ABSTRACT

A method for making a bean-based oil substitute comprising the steps of (a) homogenizing comminuted cooked beans in an aqueous liquid dispersion to form a homogenate, and (b) mixing an edible oil with said comminuted beans, before or after homogenization of the beans, to form a flowable stable dispersion oil substitute of the comminuted beans dispersed in a mixture of oil and water. The oil substitute is used to replace part of the oil in making dehydrated refried beans.

BACKGROUND OF THE INVENTION

Refried beans may be supplied to restaurants in dehydrated form forsubsequent rehydration into refried beans in the restaurant. In oneprocess for making such dehydrated beans disclosed in Huffman, et al.U.S. Pat. No. 4,676,990, beans are mixed with lard and flavoringfollowed by cooking and extrusion into pellets which are dried intodehydrated pellets. Other products substitute a vegetable oil such as ahydrogenated corn oil for the lard in this process. The dried pelletstypically include about 9% oil. Vegetable oil is relatively expensive.Also, many consumers wish to minimize oil consumption in their diets.Thus, there is a need to provide dehydrated refried beans with reducedoil content and characteristics comparable to the conventional product.

SUMMARY OF THE INVENTION

In one embodiment of the invention, a method is provided for making abean-based oil substitute comprising the steps of (a) homogenizingcomminuted cooked beans in an aqueous liquid suspension to form ahomogenate, and (b) mixing an edible oil with said comminuted beans,before or after homogenization of said beans, to form a flowable stabledispersion of said comminuted beans dispersed in a mixture of oil andwater.

Another embodiment of the invention is a bean-based oil substitutecomprising homogenized comminuted beans in a stable aqueous liquiddispersion of an edible oil and water.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow diagram of one embodiment of the method of the presentinvention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In general, the present invention relates to a bean-based oilsubstitute, particularly one for use in dehydrated refried beans, and toa method of making the substitute and its use in refried beans. As usedherein, the term “bean-based oil substitute” means a bean-based productthat can replace part or all of the oil used in a food product such asdehydrated refried beans. Thus, the term encompasses an oil extender orreplacer.

Steps 10, 11 and 12 of FIG. 1 relate to making the bean-based oilsubstitute of the present invention. Steps 13, 14 and 15 refer to theuse of the oil substitute in place of conventional oil in the making ofdehydrated refried beans.

Referring to step 10, in one embodiment, cooked beans are comminuted inwater to form a flowable aqueous suspension of the cooked beans. As usedherein, the term “cooked beans” in step 10 means beans which have beencooked at least once and may be used in step 10 prior to dehydration orafter dehydration and rehydration. Thus, the cooked beans in step 10 canbe supplied from a variety of sources. In one embodiment, the cookedbeans are dehydrated beans such as ones supplied in dehydrated form byBasic American, Inc. to the foodservice restaurant trade. Such beans canbe made by soaking dry beans in hot water to hydrate the beans, mixingthe hydrated beans with oil, cooking, and forming the beans into pelletsby extrusion, and drying the pellets. The general procedure described insteps 13, 14 and 15 may be used to make the dehydrated beans supplied asthe cooked beans in step 10. Conventional vegetable oil or an oilsubstitute may be mixed with the beans during this process.

An alternative source of the cooked beans in step 10 is the dehydratedproduct formed by the method described in U.S. Pat. No. 4,676,990. Inthat patent, lard is used instead of oil.

In other alternatives, the cooked beans can be cooked fresh beans ordried beans not previously dehydrated which are soaked for rehydration.Further, the cooking may be performed prior to, during or aftercomminution.

In communication step 10, the cooked beans are mixed with water in acomminution mixing tank to form a liquefied flowable slurry of thecomminuted cooked beans in water. In the embodiment where the beans aredehydrated pellets that are mixed with water, the water preferably isheated to accelerate rehydration of the beans in the water to form aflowable slurry. Preferably, the beans are rehydrated prior to thehomogenization step 11 to be described hereinafter.

In one form of comminution in step 10, dehydrated beans are rehydratedand “liquefied”, i.e. formed into a flowable slurry, by shearing. In oneembodiment, the beans and water are supplied to a tank and flow out thetank outlet through a shear pump which liquefies the beans. The outletof the shear pump may be split with a portion recirculating to themixing tank and another portion passing to homogenization step 11.

Prior to homogenization, it is preferable to swell the cells of thecooked beans by heating in water as prior to, during or aftercomminution, and before homogenization. Thus, the bean slurry in thecomminution mixing tank in step 10 may be heated to an elevatedtemperature, e.g., 145° F. to 200° F., preferably 180° F. to 185° F., asby use of a steam jacket around the tank.

Suitably, prior to homogenization, the beans are comminuted to a sizewhich will permit the beans to flow in a relatively low viscosityslurry-like suspension to the homogenization step. Suitable comminutionconditions can be attained by flow through a shear pump or mixeroperating at 3500 rpm.

In another embodiment, not shown, the beans may be comminuted in a dryform followed by mixing with water to form a slurry. In this embodiment,it is preferable to hydrate the beans prior to homogenization. It isbelieved that this disrupts at least some of the lipid bonds in themonomolecular layer encapsulating the bean micelles.

In yet another embodiment, the cooked beans may be comminuted prior tofull hydration. A suitable apparatus for performing comminution in thisembodiment is the same kind of shear pump described above or standardgrinder or mill.

The ratio of the water to the beans may vary over a wide range. Theratio may affect the homogenization efficiency and the desiredproperties of the oil substitute formed in step 12. For example, highviscosity slurries may be difficult to transport or pump to thehomogenizer. On the other hand, if the bean solids are too low this mayadversely affect the stability of the dispersion of the presentinvention. Suitably, the water/bean mixture includes from above 5 to 25%beans and 95 to 75% water, preferably from 12 to 15% beans and 88 to 85%water. (All percentages expressed herein are on a weight basis.) Edibleoil may be added before, during or after homogenization step 11 so longas it is present in the bean-based oil substitute when mixed with thebeans in step 13.

In step 11, the comminuted cooked beans flow in an aqueous dispersion toa homogenizer. The conditions of homogenization are analogous to theconditions of homogenization of hydrated or swollen potato granules asdescribed in U.S. Pat. No. 6,485,775. The pressures applied duringhomogenization may be as low as 1,000, 3,000 or 5,000 psig. Preferably,the pressures are in excess of 5,000 psig and more preferably in excessof 6,000, 7,000, 8,000, 8,500, 9,000, 10,000, 11,000, 12,000, 13,000,14,000, 15,000, 18,000, 20,000 psig or more. Suitable homogenizers andconditions of homogenization are described in the '775 patent. As usedherein, the term “homogenization” means reduction of the particle sizeof the beans in water to create a mixture comprised of small particlestypically characterized by a relatively uniform texture and composition.Typically, the product has an oily tactile feel, even in the absence ofoil, due to the presence of the microscopic-sized homogenized beanparticles. Preferably, during homogenization, the bean cell walls havebeen ruptured.

In an alternative embodiment, not shown, the particles may be comminutedand homogenized simultaneously.

As illustrated in step 12, the comminuted, homogenized beans in waterare mixed with an edible oil, and, optionally, an added emulsifier, toform a flowable oil substitute in the form of a stable dispersion of thecomminuted beans dispersed in a mixture of oil and water. In analternative embodiment, not shown, the edible oil may be mixed with thecomminuted beans and water prior to or during homogenization. However,this will increase the volume of liquid flowing through the homogenizerwhich leads to additional required capacity for the homogenizer.

During step 12, the mixture is subject to shearing conditions sufficientto form droplets of the oil. Suitable shearing conditions utilizeequipment such as a Silverson Model 275LS high shear in-line mixer andoperated at 3600 RPM. It has been found that, after bean homogenizationin water and mixing with oil, under such shearing conditions, a flowableoil substitute of the comminuted beans in a mixture of oil and water iscreated in the form of a stable dispersion having similar stability to aconventional emulsion. Such a stable dispersion is referred to herein asbeing “emulsified” or in “an emulsified form”, even though it may or maynot include an added emulsifier. The emulsified form of the dispersionis such that it is stable over a typical period of use of at leastminutes, hours, days or weeks. Typically, it is characterized by acreamy consistency. The oil substitute is characterized by thickerviscosity than the unhomogenized bean slurry.

It is believed that the homogenized bean particles serve an emulsifyingfunction for the oil/water mixture in step 12. The stable dispersion isbelieved to include oil in water droplets but may include water in oildroplets. In either event, small bean particles are believed to beincorporated into the fine droplets of the oil or water. These dropletsappear to be in substantially spherical form, like fish eggs, under amicroscope. The homogenate also is believed to serve an emulsifyingfunction for the oil added to cooked beans for making a dehydratedrefried bean product.

It is believed that the homogenate serves as a functional emulsifier asdetermined by its ability to hold oil in a stable dispersion withoutnoticeable separation of the oil from the water. This functionalproperty provides a sensory benefit in the finished product similar to afat mimetic which results in a product with the sensory perception of ahigher oil product but in a lower oil format. The conditions of mixingin step 12 can affect the stability of the dispersion. It is preferableto shear the mixture under sufficient energy to create fine oil dropletsto assist in creating a stable dispersion.

This bean-based oil substitute is preferably used as a substitute orreplacement of the vegetable oil used in a conventional dehydratedrefried bean process described above and as described in steps 13, 14and 15 below using the oil substitute in place of part of the vegetableoil used in a conventional product.

In step 12, an optional ingredient, an emulsifier, may be added to thebean-oil-water mixture to facilitate formation of an emulsion. However,it has been found that use of an emulsifier is not required. It may bepreferable to exclude substantial added emulsifier for someapplications. “Added emulsifier” means emulsifier added to the liquidphase, not present in the beans fed to step 12. If emulsifier is added,any of the well-known food grade emulsifiers may be used. Suitableemulsifiers include monoglycerides, mixtures of mono- and diglycerides,and derivatives thereof, including DATEM (diacetyl tartaric acid estersof mono- and diglycerides).

Mono- and diglycerides derived from either vegetable or animal fatstypically consist of a mixture of predominantly saturated acyl fattyacids including lauric, palmitic, stearic, myristic in combination withunsaturated acyl fatty acids, including oleic, eladic, linoleic andcombinations thereof. Mono- and diglycerides typically have amonoglyceride content equal to or greater than 40%, preferably greaterthan 60% and most preferably 90%. In the production of monoglycerides, atriglyceride normally is reacted with glycerol to form a mixture of monoand diglycerides. This process can be carried further to isolate or toconcentrate the monoglyceride fraction by molecular distillation. Theremaining components, predominantly di and triglycerides are typicallyrecycled back to the reaction with glycerol to make additionalmonoglyceride. Any emulsifier used can be at a relatively lowconcentration, e.g., from 0.1 to 1.0% based on oil content in thefinished product.

Suitable edible oils for use in step 12 are the oils used to makerefried beans, typically a vegetable oil such as hydrogenated orunhydrogenated corn oil. Other suitable edible oils include food gradevegetable or other types of oils, including soybean oil, coconut oil,cottonseed oil, sunflower oil, palm oil, canola oil, corn oil, oliveoil, rendered fat, lard, or combinations thereof.

While not intending to be limiting, the desirable emulsion-likecharacteristics of the present product are believed to be accomplishedby disrupting the bean cell walls and breaking them into very smallparticles and by shearing the oil into small droplets.

A suitable weight ratio of homogenized beans:oil:water is from 3 to 15%,preferably from 7 to 8% beans; 33% to 75% oil, preferably 45% to 55%oil; and from 33 to 75%, preferably 37 to 48% % water. The concentrationof beans preferably is high enough to provide the desired functionalproperties, but not so high that the resultant emulsion is unpumpable.The amount of oil is dictated by the sensory properties desired in thefinished product. Water is primarily used as a carrier.

In step 12, the oil and homogenized bean dispersion can be made bymixing in a similar way to the comminution mixing step 10 describedabove. Thus, the mixture may be recycled to a mixing tank through ashear pump with a portion of the recycle drawn off as the bean-based oilsubstitute of the present invention.

Steps 13, 14 and 15 are one conventional process for making dehydratedrefried beans except for the use of the oil substitute.

Referring to step 13, the oil substitute product from step 12 is mixedwith beans and processed as in a conventional process for producingdehydrated refried beans. In such process, beans, typically dried pintobeans, are soaked in water at elevated temperature to swell them.Suitable presoaking conditions are 180° F. for 15 to 20 minutes.Thereafter, the presoaked beans may be cooled as in tap water anddrained.

The beans may be mixed with the oil substitute from step 12 and cookedduring mixing. Alternatively, the beans may be cooked before or aftermixing. Suitable mixing conditions for the oil substitute and beansinclude any conventional means such as mixers, tumblers, or the like.

Alternatively, fresh or cooked undried beans could be used. If the beansare not cooked, in step 13 the beans may be cooked while mixing.Suitable mixing conditions can be accomplished in a rotating pressurecooker. Beans may be cooked during mixing or before or after mixing. Theconditions of cooking are conventional such as for a time of 44 minutesat 256° F.

Suitable additional ingredients which may be added in or prior to step13 include flavoring ingredients such as dendritic salt (e.g., at aconcentration of 1 to 5% based on the beans) and also, if desired,additional oil.

In step 14, the mixture of step 13 is formed into the desired pelletform as by extrusion. Suitably, the size of the pellets are ⅛ to ⅜ inchin diameter and random length. Then the product is dried in step 15.Steps 14 and 15 can be accomplished using the conditions set forth inHuffman U.S. Pat. No. 4,676,990.

The dried product typically has a moisture content of about 4 to 10%.The dried pellets exiting from step 15 are similar to conventionaldehydrated refried beans except for the use of the oil substitute. Asuitable oil content in the pellets is below the conventional oilcontent of 9%, that is, less than 8%, 7%, 6%, 5%, 4%, 3%, 2% or less.Alternatively, the oil content can be maintained at 9% or above, andhomogenate added in order to increase the sensory perception of oil. Thefunctions of the homogenate include substitution for the oil used in aconventional product, and enhancement of the reconstituted yieldcapability in the finished refried bean product.

The bean-based oil substitute provides the sensory benefit in thefinished product of a fat mimetic which results in a product with thesensory perception of a higher oil product but in a lower oil format. Inaddition, a 3-5% increase in reconstituted yield can be expected forexample when a 6% oil (dry basis) refried bean with homogenate added, iscompared to a 9% oil control product.

A suitable ratio of components of the dried pellets are (a) about 3 to11%, more preferably about 6 to 9% water; (b) about 75 to 91% beansolids; and (c) at least about 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or more,and more preferably 3 to 8% oil, more preferably 4 to 7%.

The above dehydrated refried bean product typically has an improvementin rehydration ratio or yield compared to a conventional refried beanproduct due to the replacement of part of the oil with bean solids.Percent increase in yield may be in excess of 1%, 2%, 3%, 4%, 5%, 6% ormore to achieve the standard refried bean viscosity. For example, aconventional dehydrated refried bean product typically has a rehydrationratio of approximately 2.97 to achieve this standard refried beanviscosity. One product of this invention has an approximate rehydrationratio of about 3.07 to achieve the same standard refried bean viscosity.The net effect is that with the product of the current invention, about5% less dehydrated product can be packed in a bag for reconstitutionwith the same amount of water. This results in a 3.4% improvement inrehydration ratio or reconstituted yield. Thus, a dehydrated refriedbean product according to the present invention has a rehydration ratioin excess of 3.0, preferably in excess of 3.02, 3.04, 3.06, 3.08, 3.10,or more.

Taste panel tests showed that the product of the present invention hadsimilar consumer preference acceptance to a conventional dehydratedrefried bean product in appearance, aroma, flavor, texture, andaftertaste, using standard testing procedures such as set forth inMeilgaard et al., Sensory Evaluation Techniques, 3^(rd) ed., CRC Press,Chapter 12, pages 241-249.

In order to illustrate the present invention, non-limiting examples ofits practice are given.

EXAMPLE 1

A bean/water slurry is formed by weighing 1.5 pounds/minute ofdehydrated refried beans through a bean feeder and metering 8.5pounds/minute of hot water (180 degrees F.) into the rehydration tank.

This slurry is continuously circulated through a Silverson 275LS shearmixer with a general purpose disintegrating screen at a rate ofapproximately 50 pounds/minute. A partial stream (10 pounds/minute) ofthe sheared refried bean slurry is pumped to a Niro Soavi homogenizerset at a 12,000 psi operating pressure. The resulting homogenate iscombined with a 10 pound/minute stream of hydrogenated corn oil andpumped through a Silverson 275LS shear mixer equipped with an emulsionscreen and the resulting emulsion is discharged into an agitatedemulsion tank in a stable dispersion.

Then, refried beans are made in a continuous process using thishomogenized bean/corn oil stable dispersion. In this process raw beansare washed and transferred to a vessel where they were soaked at 180° F.for 30 minutes. These soaked beans (1,800 pounds), salt (35 pounds), andthe emulsion (120 pounds) are pumped into a pressurized kettle. Thebeans are then cooked in the kettle at 255 F. for 30 minutes. Once thebeans are cooked, they are removed from the cooker and extruded througha die plate with ⅜ inch openings onto a Proctor Dryer where they weredried to a 6.5% moisture content. The total oil content in the beans wasabout 6%.

1. A method for making a product suitable for use as dehydrated refriedbeans comprising the steps of: (a) homogenizing comminuted cooked beansin an aqueous liquid suspension to form a homogenate of said beans, (b)mixing an edible oil with said comminuted beans, before or afterhomogenization of said beans, to form a flowable stable dispersion ofsaid comminuted beans dispersed in a mixture of oil and water to make abean-based oil substitute, (c) mixing said oil substitute with cookedbeans, (d) forming said mixture into desired shapes, and (e) drying saiddesired shapes into a product suitable for use as dehydrated refriedbeans.
 2. The method of claim 1 in which said oil is mixed with saidcomminuted beans after homogenization of said beans under conditions toshear said oil into droplet form, which droplets form part of the stabledispersion.
 3. The method of claim 1 in which beans are cooked,dehydrated, rehydrated and comminuted, to make said comminuted beans. 4.The method of claim 1 in which said aqueous liquid suspension ofcomminuted beans is directed in a flowable stream to a homogenizer forsaid homogenizing step.
 5. The method of claim 1 in which said oilsubstitute further comprises an emulsifier, and said oil substitutebeing in the form of an emulsion.
 6. The method of claim 1 in which saidoil is a vegetable oil.
 7. The method of claim 6 in which said vegetableoil is at least partially hydrogenated.
 8. The method of claim 1 inwhich said oil is lard.
 9. The method of claim 1 in which said oilsubstitute comprises about 33% to 75% oil, about 33 to 75% water andabout 3 to 15% comminuted beans.
 10. The method of claim 1 in which saidforming is performed by extrusion.
 11. The method of claim 1 in whichthe oil content of said dried product is less than about 15%.
 12. Theproduct suitable for use as dehydrated refried beans made by the processof claim
 1. 13. The method of claim 1 in which said homogenization isperformed at a pressure of at least 5000 psig.
 14. The method of claim 1in which said mixed cooked beans of step (c) are undehydrated.
 15. Abean product comprising homogenized comminuted beans of microscopic sizein a stable aqueous liquid dispersion of edible oil and water, inadmixture with cooked beans formed into desired shapes and dried into aproduct suitable for use as dehydrated refried beans, in which the totaloil content of said dehydrated refried bean product is less than about15%.
 16. The bean product of claim 15 wherein said oil substitutefurther comprises an emulsifier and said oil substitute is in the formof an emulsion.
 17. The bean product of claim 15 without any substantialamount of added emulsifier in said dispersion.